Reverberation Chamber RF Production Testing
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Solution Overview
Problem
Conventional reverberation chambers are cumbersome and time-consuming for production testing of electronic devices like mobile phones and laptops, leading to high uncertainty and increased costs due to the need for isotropic environments and cumbersome measurement processes.
Innovation Solution
A method and apparatus using a smaller reverberation chamber with inwardly facing electromagnetically reflective walls, allowing for static mode distribution configurations to measure radio frequency transmission, comparing results to a 'golden standard' device to determine device acceptability, enabling faster and more cost-effective production testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional reverberation chambers are used for production testing, then measurement reliability is improved, but testing time and cost increase significantly
Solution Approach 1:
The patent changes the measurement parameters by using a limited set of predetermined mode distribution configurations instead of exhaustive measurements. This allows the system to achieve sufficient measurement reliability for production testing while dramatically reducing testing time and cost compared to conventional reverberation chamber methods.
Solution Approach 2:
The patent applies partial action by measuring only at a selected number of predetermined mode distribution configurations rather than performing complete exhaustive measurements. This partial measurement approach provides sufficient reliability for production testing while avoiding the time-consuming nature of full reverberation chamber characterization.
2Measurement precision
If conventional reverberation chambers are used for production testing, then measurement accuracy is improved, but chamber size and complexity increase
Solution Approach 1:
The patent changes the spatial and temporal parameters of measurement by selecting specific predetermined mode distribution configurations. This approach maintains measurement accuracy for production testing purposes while avoiding the need for large, complex conventional reverberation chambers with exhaustive measurement capabilities.
Solution Approach 2:
The patent extracts only the essential measurement information needed for production testing by selecting a limited set of predetermined mode distribution configurations. This extraction approach maintains sufficient measurement accuracy while eliminating the unnecessary complexity of full reverberation chamber systems.
3Productivity
If shielded boxes with RF absorbing materials are used, then testing speed is improved, but measurement reliability decreases
Solution Approach 1:
The patent changes the electromagnetic environment parameter from anechoic (RF absorbing) to reverberant (reflective walls with predetermined mode distributions). This allows the system to maintain fast production testing speeds while significantly improving measurement reliability through controlled multipath signal propagation.
Solution Approach 2:
The patent converts the traditionally harmful effect of signal reflections and multipath propagation into a beneficial feature for measurement reliability. By using reflective walls and predetermined mode distribution configurations, the system transforms what would normally be interference into a means of obtaining more reliable production test results.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces production testing time and cost while improving reliability in distinguishing between faulty and acceptable devices, allowing for simultaneous testing of multiple devices with reduced chamber size and complexity.
Implementation Method 1
walls having inwardly facing surfaces of an electromagnetically reflective material, thereby supporting several resonant modes within the internal cavity
Implementation Method 2
The signal arrives at the device under test after multiple reflections through many different trajectories
Implementation Method 3
By moving mode stirring plates and/or the turntable the geometry of the chamber changes, which in turn changes the fading that the signal experiences
Data Source
AI summary
A method and apparatus for production testing of a device under test (DUT) in a chamber is disclosed, the chamber defining an internal cavity therein, adapted to enclose the DUT, and including walls having inwardly facing surfaces of an electromagnetically reflective material, thereby supporting several resonant modes within the internal cavity. The method comprises: arranging the DUT at one or several measurement position(s) in the internal cavity; measuring radio frequency transmission between the DUT and at least one chamber antenna arranged in the internal cavity sequentially in a number of different static mode distribution configurations; comparing the measured radio frequency transmission at said predetermined mode distribution configurations with reference values obtained from measurement of a reference device arranged at the same measurement position(s) within the internal cavity, and at the same static mode distribution configurations; and determining whether the DUT is acceptable or non-acceptable based on said comparing.